Labelling machines of this type are equipped, not only with means of unrolling the band which is wound on a supply reel, but also means of winding up the band from which the labels have been stripped after its passage over the distribution plate. In addition, the sharp angle at the level of the distribution plate is formed by driving the band over at least two deviating bars placed close to said plate and in such a way as to deviate the band from its path running from the supply reel towards the receiving reel.
The aforesaid band moving means assembly is controlled in relation to the way in which the articles to be labelled are presented, generally by means of a mechanical or opto-electronical sensor, provided at the level of the conveyor on which said articles are moved.
Such a machine is further equipped with extra accessories provided for slowing down the unrolling of the supply reel, for adjusting the tension of the band particularly when said band reaches the part between the two deviating bars and the distributing plate so that the band remains stretched and that the labels can be stripped from their non-adhesive base in the best conditions, even if the progression of the band is jerky, such accessories consist in particular in multiple tension rollers for tensioning the band, or flexible bars which are applied against the band, etc.
Therefore, the conventional labelling machine of this type which the Applicant knows of have a complicated and bulky structure due especially to the presence of all the aforesaid accessories provided on the path of the band.
Another labelling device is known from U.S. Pat. No. 3,113,904 in which the label stripping device consists in a heated print wheel and not in a sharp-angled distribution plate. Nonetheless, said device is equipped with a brake assembly acting on the feeding of the band. Said brake assembly is composed of a brake-pad which can be applied against a drum fast with the spindle of the supply reel, of a pivotable bent lever carrying at one end the brake-pad and at the other end a guide roller for the band, and finally of a draw spring which is fast with a lever and which tends to apply the pad on the drum. In operation, the displacement of the band induced by a toothed wheel creates a tension on the band and, correlatively, causes the guide roller to move and the lever to pivot. Such pivoting movement of the lever releases the pad which was in contact with the drum, and enables the reel to turn around its spindle, hence causing the band to move forward.
This system, however, works jerkily and is not entirely satisfactory.